[meteorite-list] Something Different To Consider About
From: Mark Fox <unclefireballmtf_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:30 2004 Message-ID: <20020427184919.21516.qmail_at_web14905.mail.yahoo.com> April 26, 2002 Greetings Meteorite Enthusiasts! With the startling news announced by European Fireball researchers in regard to the EN060402 bolide being linked with the Pribram chondrite, fellow enthusiasts on the Meteorite-list are likewise trying to make "connections". However, I must say something that may not have been considered. When trying to discover a "meteorite" stream (meteoroid is the better term here) we should not just consider or try to link meteorite falls of only one distinct type with each other. In reality, the composition of such a stream composed of asteroid matter is quite likely not to be homogenous! Dr. Pavel Spurny in his history making e-mail had this little footnote to add: "Finally, from the perfect similarity of both heliocentric orbits we can predicate, that both bodies had also the same composition and therefore we can expect that meteorites produced by the April 6 fireball are H5 ordinary chondrites." Astounding! I was intrigued that such a bold statement was made, especially in such a mysterious and sparsely understood whelm. However, in this case, I believe the logic which drew the conclusion should be revised. Just because the orbital data and/or fireball information of both meteorite falls are so similar doesn't mean that they are one in the same meteorite, petrologic type and all! Asteroids almost undoubtedly vary in overall composition as one nears the core, which does of course assume we are talking about a good sized asteroid body to begin with or a big fragment from such. With the discovery of so many asteroid moon systems recently, we again should not be so certain that the two linked meteorite falls have almost equal compositions. For all we know these asteroid moons could form a hefty percentage of a rocky meteoroid stream, ones with slight petrologic and composition differences or entirely different classes! Gravitational pulls by our planet could be prying them loose from the "mother ship" asteroid during close encounters. As a result, the behavior of such a stream could be noticeably different from that of a normal cometary meteoroid stream. Something else to keep in mind. In conclusion, chondrites of different petrologic types (or possibly even meteorites of different classes) should not necessarily be excluded when trying to identify a date(s) that a possible meteoroid swarm is encountering Earth. Also, EN060402 does not necessarily have to be an H5 chondrite as is Pribram when one "digs" more deeply into the compositional nature of asteroids. Lastly, the behavior of an asteroid meteoroid stream may involve new methods of sending material to Earth. All the above is my personal slant and I am open to all comments on this matter. Please correct me for any possible errors. Long strewn fields! Mark Fox Newaygo, MI USA __________________________________________________ Do You Yahoo!? Yahoo! Health - your guide to health and wellness http://health.yahoo.com Received on Sat 27 Apr 2002 02:49:19 PM PDT |
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